In order to satisfy ever-increasing demands for wireless data traffic, techniques for increasing data rate in a wireless communication system have been proposed. One of the techniques is to increase the bandwidth of a signal. Because securing a broad frequency band in a bandwidth of 10 GHz or below in a general wireless communication system is difficult, a broad frequency should be secured in a higher frequency band. In this context, short-range communication standards in the current 60-GHz frequency band, such as Wireless High Definition (WirelessHD), Institute of Electrical and Electronics Engineers (IEEE) 802.15.3c, IEEE 802.11ad, and the like are under active study for millimeter wave communication systems.
As a result of the use of an extremely high frequency, a millimeter wave communication system suffers from path loss, poor penetration characteristics, and thus a reduction of service coverage. Such problems may be solved by beamforming. Specifically, narrow beam-based beamforming restricts Doppler spread and multi-path components.
Beamforming focuses waves on a specific service area by steering (e.g., directing) signals from a plurality of antennas in a specific direction. Beamforming may include Transmission (Tx) beamforming and Reception (Rx) beamforming. In Tx beamforming, almost no signal is transmitted in directions other than an intended direction. In contrast, in Rx beamforming, almost no signal is received from directions other than an intended direction. For the Tx beamforming and the Rx beamforming, a transmitter and a receiver may need to detect respective best Tx and Rx beams that have highest signal strengths by sequentially steering beams in specific directions.
Meanwhile, when a Mobile Station (MS) initially accesses a Base Station (BS) or performs handover to the BS, the MS performs a Random Access (RA) procedure. The process of detecting best Tx and Rx beams may be performed during the RA procedure. Accordingly, RA is delayed by a time taken to detect the best Tx and Rx beams.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.